Hi David,
BRP stands for Bombardier Recreational Products, they make amoung other things, SeaDoo, SkiDoo, CanAm, Johnson/Evinrude, the parent company makes the Canada Air Regional Jet.
Just ask for injection oil for a SeaDoo 2 stroke, API-TC, SeaDoo XPS, or equivalent. Do you know what oil the previous owner used, if you do you should use the same. If you don't know you will need to drain the old oil, add fresh oil and purge the system.
For Yamaha all you need is TC-W3 which is basically outboard engine oil, sorry I don't know Yamaha all that well to advise you what to use.
Lou